Let $T = (X, \mathcal{T})$ be a D1106: Topological space such that
| (i) | $E_1, \ldots, E_N$ are each a D98: Closed set in $T$ |
Then $\bigcup_{n = 1}^N E_n$ is a D98: Closed set in $T$.
| (i) | $E_1, \ldots, E_N$ are each a D98: Closed set in $T$ |